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Protozoa Classifications
Method of Locomotion
- flagella
- cilia
- pseudopods 
- apical microtubule complex
Helminths (worms)
Round Worms
- Tissues
- Intestines

Flat Worms
- Flukes
- Tape Worms
Ectoparasites
- arthropods or arachnids (lice, scabies, ticks)
Definitive vs Intermediate host
Definitive host - parasite reproduces sexually
Intermediate host - parasite reproduces asexually
Entamoeba histolytica
- Life Cycle
- Distribution
- Manifestation
- Treatment
- pseudopod, amoebae, unicellular, protozoa
Life Cycle
1) cyst (excreted)
2) ingested (contaminated food + water)
3) attachment (colonic mucosa) + penetration (portal circulation)
4) cyst formation
- Mexico (US = Rare)
- Diarrhea, Liver Abscess
- Metronidazole
Acanthamoeba
- "homemade saline" - cornea amoeba
Giardia lamblia
- EXPLOSIVE, frothy, smelly diarrhea (inhibit fat ab.)
- acute disease (1-4 wks w/o treatment)
- vegetative (intestinal) + cyst (infectious) form. Extracellular
- cyst-infected water / fecal-oral
- "bever fever" - animal resevoir, ingestion pathogen
- IgA deficiency @ risk
- worldwide
Cryptosporidium spp. (Parvum)
- prolonged diarrhea (from sporozoite, trophozoite, merozoite)
- sporozoite = brush boarder (intracellular), trophozoite = intracellular
- cyst = infectious form
- cattle feces in water
- worldwide (2 decades ago - Wisconsin)
- acid fast stain
- immunocompromised
Microsporidia
- diarrhea - Immunosuppressed / AIDs patients
- Important to treat immuno deficiency
Trichomonas vaginalis
- women only (men asymptomatic)
- frothy, fish-odor vaginal discharge
- pear-shaped w/ twitching motility
- metronidazole
Plasmodium spp.
- malaria (grows in RBC) - fever + headache - anemia.
- "ring form"
- falciparum (most lethal - no dormant stage + year round), ovale, vivax (dormant liver stage), malariae

Uncomplicated: Cyclic Fevers (every 48 hours)
pfEMP - binding to RBC: + binds to endothelial cells: obstruction to tissue perfusion -> multiorgan failure
- Ring form blood smear
Babesia
- tick vector -> non-human vertebrates (deer + mice)
- infects erythrocytes
- US (Nantucket Island, Martha's Vineyard, Cape Cod)
Leishmania spp.
- veterans from Iraq w/ skin ulcerations
- sand flies
- skin lesions (deformed face) + hepatosplenomegaly
Trypanosoma spp. (2 forms)
(brucei + cruzi)
- Cruzi: South America - "kissing bugs" => Chagas' disease (colon dysmotility, heart failure) - intracellular stage (no variation)
- Brucei: Africa - Tsetse fly - Sleeping Sickness (meningo-encephalitis)

- Disease: Stage 1 = chancre + lymphadenopathy. Stage 2 = CNS involvement
- Life Cycle: Trypomastigotes -> binary fission in humans
- Epimastigotes -> w/in Tsetse fly
- Metacyclic Trypomastigoes -> transferred to humans in bite.
- Variable Surface Glycoprotein (VSG) -> Gene conversion -> recombination due to change of promoters -> expression of new VSG
- epidemiology, blood smear, CSF (Stage II)

Roundworms (Intestinal)
- Ascaris lumbricoides, Hookworm, Pinworm, Strongyloides stercoralis, Whipworm
- GI (females produce eggs) 
- ingestion of eggs (ascaris, pinworms, whipworms) OR larval forms (hookworms, strongyloides) 
- GI -> blood -> lungs (cough) -> GI 
- rural areas (soil) 
- Albendazole or ivermectin, praziquantel for pinworms.
Hookworm
- type of roundworm
- cutaneous larve migrans (crawl into skin)
- cat + dog feces
Pinworm
- perianal itch
- scotch tape on butt to look for eggs
- treat entire family
Roundworms (tissue)
- Filarisis (larve from mosquitoes)
- Onchocerca - blindness (blood infection)
- Elephnatiasis - lymphatic obstruction
Strongyloides
- Pneumonia, abdominal pain, skin rash, bacterial sepsis
- vietnam, thai, south US (look for veterans)
Flatworms (flukes = trematodes)
- schistomose - lungs + liver -> adult worms -> GI -> eggs -> feces -> snails
- Katayama Fever (allergic rxn) -> chronic (liver, bladder cancer, neurologic)
- praziquantel (membrane permeability)

Life Cycle

- snail (intermediate host) -> fresh water
- human entry into snail wate (lake malawi)
Flatworms (Cestodes = Tapeworms)
- neurocysticerocosis (larval cysts in the brain) - seizures
- Pork -> systemic cyst -> human (ingest eggs or undercooked meat) -> GI -> tapeworm -> eggs

Hydatid disease
- Tapeworm (cestodes) from dogs
- echinococcus granulosus
- GI -> oncospheres -> liver cysts
- cyst rupture -> septic shock

- Iraq and Middle East
Lice
- ectoparasite
- nits, body lice, crabs.
- can hold Rickettsiae
Scabies
- ectoparasite (arachnid)
- extremely itchy infestation from allergic reaction to feces 
- skin scrape
Myiasis
- larvae of flies (maggots)
- do NOT pull out
- cover up with tape.
Anti-malaria Drugs
- Chloroquine (resistance)
- Quinine
- Primaquine (exoRBC, liver)
- Arthemisinin
- Mefloquine (prophylaxis)
- Atovaquone/proguanil (pro / treat)
Plasmodium Lifecycle
Sporozoite -> Liver Schizonts (Maturation) -> Merozoites -> RBC -> Ring, trphozoite, schizont -> fever cycle
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